import java.util.Stack;

public class Test {

    //括号匹配
    public boolean isValid(String s) {
        Stack<Character> stack = new Stack<>();
        for (int i = 0; i < s.length(); i++) {
            char ch = s.charAt(i);
            if(ch == '(' || ch == '[' || ch == '{'){
                stack.push(ch);
            }else{
                if(stack.empty()){
                    return false;
                }
                char top = stack.peek();
                if(top == '(' && ch == ')'
                || top == '[' && ch == ']'
                || top == '{' && ch == '}'){
                    stack.pop();
                }else{
                    return false;
                }
            }
        }
        if(!stack.empty()){
            return false;
        }
        return true;
    }


}
